Follow these straightforward steps to create your icing:

1. Mix Base: In a bowl, combine the powdered sugar and corn syrup. Stir until well blended.
2. Add Liquid: Gradually stir in the milk or water. Adjust the amount to achieve your desired icing thickness. The consistency should be thick enough to hold its shape but thin enough to spread easily.
3. Add Flavor: Mix in the vanilla extract or your preferred flavoring. This adds depth and a delightful aroma to your icing.
4. Color: Divide the icing into separate bowls if you plan to use different colors. Add gel food coloring to each bowl, mixing thoroughly until you reach your desired shades.
5. Decorate: Transfer the icing to a piping bag or use a spoon to spread it over your cooled sugar cookies. Get creative with your designs!
6. Let Set: Allow the decorated cookies to dry at room temperature until the icing hardens. This may take a few hours depending on the humidity and thickness of the icing.